Wire feeding mechanism



Nov. 5, 1963 D. T. Tllr-:oDoRE 3,109,571

WIRE FEEPING MECHANISM David T. Theodore IN V EN TOR.

ATTORNEY Nov. 5, 1963 Filed Nov. 16. 1960 D. T. THEoDoRE 3,109,571

WIRE FEEDING MECHANISM 2 Sheets-Sheet 2 FIG.3

l |M|\ im ."Li 44` 28 35 l 3o l I l l l 51 21- I 22 s l`a16 5l l l l I l JNVENToR. David T. Theodore UWM ATTORNEY United States Patent O 3,199,5751 WlRE FEEBENG F/lECilANlSlyl David T. Theodore, East Grange, Nd., assigner to The Dore Development Co., Enc., Silver Spring, hid., a ecrporation Filed Ney. 16, 1969, Ser. No. @,li 8 Claims. (Cl. 226-l67) This invention relates to a wire feed mechanism and, more particularly, yto a wire feed mechanism having a predetermined and easily adjustable amount of lost motion in the wire feeding direction. The invention is particularly adaptable to cyclic operations wherein operations are performed on a wire, with the wire stationary, during a major part of an operating cycle w'nich includes feeding of the wire.

In my prior U.S. Patents Nos. 2,564,739 and 2,696,013, I have shown and :described novel nail producing die sets eas-ily attached to and operated by punch presses and the like, the die sets being mountable on the holsters of such presses and operated by the vertically movable rams thereof.

In mechanical punch presses, a main drive shaft is rotated by a motor, preferably through reduction gearing and/or sheaves, and the shaft has `a crank and connecting rod for reciprocating the press ram. The wire feed mechanism of the invention is designed for operation by a pitman rotatable with such shaft and, while panticularly useful with such nail producing die sets as attached to and operated by such presses, is also us-eful in feeding wire to any other type of wire working mechanism cycllcally operated by a mechanical punch press. However, solely for the purpose of providing a specie operating example of the invention, it will be described as used in feeding wire to such mechanical punch operated nail producing die sets.

Basically, the invention is based upon the principle or concept of using the wire feed mechanism associated with cyclical-ly operable wire working mechanism as a means for introducing a controlled time delay in one operation or part of the cycle, and more particularly in that part of the cycle wherein work is still being performed on -fed wire. The feed mechanism of the invention, being connected for direct operation by the rotating shaft which also, through the punch ram, operates the wire working means, necessarily operates in direct relation to the working means.

In a complete operating cycle of the punch press, the wire must be stationary during that part of the cycle wherein the wire is being worked. For example, the wire must be stationary during the cutting, pointing and heading operations of a nail producing cycle. During at least a part of the balance of the cycle, the wire must be fed o-r moved to the wire working means. This feeding must be effected during the time the wire Working dies are opening and re-closing.

In a feed mechanism reciprocating along the wire, and considering one revolution otf a pitman operating the feed mechanism, the latter is moved in one direction along the wire during approximately 180 of the cycle or revolution, and in the other direction dong the wire during the succeeding approximately 180 of the cycle. For eX- ample, during the first 180 of the cycle, the feeding mechanism advances or feeds the wire. In the succeeding 180 of the cycle, the feed mechanism moves reversely along the wire with the wire being stationary. In these operations, back Ilash in the operating connections will occur during some of the 180 of each half cycle.

However, in many wire working operations, particularly nail production, the wire working cycle, including closing the dies, forming the head and point, severing the wire and opening the dies, utilizes more than 180 ot' the revolution of the pitman and crank shaft. Hence, an eiicient wire feeding mechanism, without appreciable back lash and looseness of connections, operating during the second half of the total cycle will start to feed wire to the working mechanism before the dies are fully open. Thus, the fed wire will encounter an obstruction in the form of the only partly opened dies. Nevertheless, such a relatively tight and efiicient wire feed mechanism is essential for high speed operations.

The only way to prevent such obstruction of the wire feed is to delay the start of feeding of the wire for the initial part of the second half of the total cycle and until the dies yare fully re-opened. However, such `delay is not readily attainable in practice while still maintaining an overall eicient operation, particularly at high speeds.

For example, purposeful introduction of back lash and loose connections to provide the requisite time delay results in the mechanism being completely unsuited for high speed operation. Geneva .gearing and other forms of intermittent motion mechanisms are also unsatisfactory and inaccurate at high speeds.

In accordance with the present invention, it has been found that quiet, smooth, elcient and accurate operation at high speeds, and in a short feed time par-t of the cycle, can be attained by the use of a wedge type of feed. By changing the slope of vthe wedges, accurate setting of the feed time is easily attained and adjusted at will..

More particularly, a pair of feed rollers are arranged one on each side of the wire to be fed, and these rollers are rotatable in a carriage or slide having a pair of wedges each engaging one of the rollers. This carriage is connected to the pitman of the crank shaft of a mechanical punch press so that the carriage is reciprocated longitudinally of the wire during each rotation off the crank shaft. As the carriage is moved toward the press, the rollers roll down the wedges until they rmly grip the wire, this occurring during an initial period of each half cycle, the length of the initial period being determined by the slope of the wedges. When the rollers grip the wire, the wire is then fed toward the press during the remainder or feed time of the half cycle. lWhen the movement of the carriage is reversed, at the end of the half cycle, the rollers roll up the wedges, disengaging the wire. Suitable means, such `as a second stationary wedge and roller cage assembly, is provided to prevent reverse motion of the wire.

For an understanding of the invention principles, refer ence is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawing. `In the drawing:

FIG. l is a side elevation View of a wire feed mechanism embodying the invention, also illustrating, somewhat schematically, associated parts of a mechanical punch press operating the feed mechanism `and a wire working mechanism;

-FlG 2 is a top plan view of the feed mechanism;

EIG. 3 is a transverse sectional view thereof, taken on the line 3--3 of FIG. 2;

FIG. 4 is a transverse sectional View of the: carriage, taken on the line fl-f-l `of FIG. V2;

FlG. 5 is a longitudinal sectional =View of the carriage, taken on the line 5 5 of FIG. 4;

FG. 6 is a bottom plan view of the carriage; and

FIG. 7 is a schematic view illustrating the wire feeding action.

Referring to FIG. 1, the wire feeding mechanism lll of the invention is illustrate-d, by way of example, as arranged for feeding wire W to a wire mechanism, such as a nail producing die set of the type shown in my said prior patents as mounted on the base or bolster of la mechanical punch press whose ram is reciprocated vertically by `a rotatable crank shaft 14 having a pitman 15. As

described in said patents, during its downward stroke, the ram openates the die set, through suitable cooperating links .and linkage on the ram and die set, to point, head, Vand cut nails. This downward stroke of the ram occupies about one-half revolution of shaft sld. The other onehalf of the revolution is utilized to re-open the die set yand feed another length of wire W thereinto.

Wire feed mechanism iti includes a support structure 2@ mourned for longitudinal adjustment along a bolster plate or support base i6 disengagedly secured to the press. The under-surface of base 2l of structure Zit and the top surface of support base i6 are formed with cooperating key-ways receiving a key 22. Structure 2@ is `clamped in longitudinally adjusted position on base ld by means of studs 23. Structure Ztl includes integral end walls 2d, interconnected by a web 26. integral with one end Wall 2d and projects horizontally outward therefrom, shelf 2S being braced by a triangular web 27. Y

The upper end of each end wall 2li is formed with a pair of laterally spaced apertures 2S, corresponding apertures in each end wall being axially aligned. Apertures 23 receive a pair of elongated guide rods 3d which project beyond one end wall over shelf 25. Rods 3? are longitudinally anchored by a pair of drift pins 3i provided with extraction nuts Each rod Sii has an axial passage 33 extending from one end to a point substantially midway between end walls 2li, the inner end of each passage 33 being interseeted by radial passages 3dr. The outer ends of passages 33 receive lubrication fittings 36.

`Midway between rods Eil, each end wall 24 nas mounted therethrough a wire guide bushing 35, bushings 35 being coaxial land locked in place by nuts 37.

Rods 3Q slidably support a carriage di) for the wire feed means. `Carriage iti is essentially a rectangular block having-a central rect-angular recess 4l in which is seated the components of the Wire feed ymeans genenally indicated at di). The wire feed means is disengageably retained in recess 4l by upper and lower pairs of bars '42 secured to carriage iti by studs d3, each bar extending partially over recess or aperture lil. Carriage dit has central apertures 4d, coaxial with guide bushings 35, and apertures 46 receiving rods 3i). The laterally opposite ends of carriage it? have vertical slots 47 forming forks.

Slots i7 receive rollers 4S on the free upper ends of rocker arms Sii, b integral with trunnions 5l, 5l disposed on either side of base Il. A T-shape reinforcing web 52 interconnects arms Si?, Sti above web 2d. Keys 53, 53 secure trunnions 5l, 5l to rotate with a rock shaft 55 having -bushinged bearing engagement in a transverse aperture 5d in base 211. f

A crank arm fie" is integral with the outer end of trunnion 5l and with a reinforcing web 56 extending between arms 45 and 50. Crank arm i5 is offset angularly from rocker arms 5d, Sti', and its free end is apertured for connection to an elongated rod or link i7 connected to pitman l5 or to an eccentrically positioned stud. The relative nadial lengths of pitman l5 and crank arm d5 are so correlated that, when crank shaft ld is rotated, arm

t5 is oscillated through a predetermined angle., Through shaft 55, rocker arms Sil, S9 and rollers d8, this oscillation of crank arm Sti results in reciprocation of carriage il along rods Sil.

Referring lmore particularly to FlGS. 4-7, wire feed means 6i? includes laterally spaced pairs of upper and ylower bars or straps 6l `arranged in aperture (il above and'below a pair of interchangeable wedges 65 having slopingsurfaces facing each other and converging toward each other in the direction opposite to the direction of wire feed. A pair of circumfcrentially grooved wire feed rollers 7d are disposed between each pair of upper and lower bars di and engaged with the sloping surfaces of wedges 65. Rollers 7@ are retained in position by a retainer or cage c62 comprising end walls 63, ed integrally Y interconnected by a circularly apertured upper web 66 A shelf isY having its side edges disposed closely adjacent upper bars 6ft. End wall 63 has a wire lead-in aperture 67 and end Wall dd has an aperture 65 coaxial with a spring seat-ing recess 7l. Recess 7l seats one end of a :coil spring 75 Whose other end is seated in a recess in the leading edge of aperture Kil. Spring 75, through retainer 62, biases rollers 79 to roll down the converging edges of wedges 65s'.

A second carriage assembly fili', identical to carriage Atti except for being slit at its ends for clamping, is clamped to rods 3d over shelf ZS. Further description of carriage ssem'bly Kid', its wedges 65', 65 and its grooved rollers d', 7d', is believed unnecessary except to state that carriage assembly liti locks the wire W 'against retrograde movement upon return movement of carri-age 4t?.

The operation of the feeding mechanism will be exained with reference to FiG. 7. When, during subantially of revolution of crank shaft 14 and pitrnan i5, carriage d@ is moved in the Vwire feeding direction, 4the rollers 7i? are at the upper or narrower ends of wedges 65. As carriage le is so moved, the wedges 65 move with it so that rollers 7i? roll down the wedges 65 toward the thicker ends of the latter. After a pre-set movement along wedges 65, determined by the angle Vof slope of the readily interchangeable wedges, rollers 70 bite into wire W and the latter is moved in synchronism with .the wedges and carriage 4t). As carriage 40' is stationary, `this movement of wire W rolls rollers 70' up the wedges 65.

At the end of this half cycle, the motion of carriage d@ is reversed. Rollers 7d now roll up wedges 65, releasing their grip on wire W. Any tendency of wire W to -rnove away-from the press -is resisted lby rollers 79 which, upon occurrence -of any such wire movement, roll down wedges 65 to grip wire W and prevent its retrograde movement. The del-ay between starte-f the half cycle and start of wire feeding is easily pre-set by selecting wedges 65 having the requisite angle of slope, as this angle determines the time lag before wire feeding starts in any Vhalf cycle.v rfhe indentations or feed marks Sil in wire W, made by rollers 74B, serve to de-limit the wire pieces produced by the wire working mechanism. The feeding is smooth, both as to acceleration and rate, and readily adapted to high speed operation.

The purpose of making support structure Zit longitudially adjustable is to position the feed mark (where rollers 76"bite into wire W) at such a location that it will appear at the point of the formed nail and thus will disappear as scrap.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the invention principles, it will be understood that the invention may be embodied otherwise ywithout departing from such principles.

What is claimed is:

ll. Wire feeding mechanism comprising, in

pl st combination,

v a carriage cyclically reciprocaible longitudinally of the wire and formed for passage of the wire longitudinally therethrough; a pair of wedges interchangeably mounted in said carriage on either side and laterally spaced from the path of wire movement therethrough; said wedges having facing sloping surfaces diverging in the direction of wire feed at a preselected slope angle; and a pair of rollers rotatable in said carriage in engagement with said sloping surfaces on either side of the path of wire movement; said rollers, upon movement of said carriage in a wire feeding direction, rolling along said slopinf7 surfaces in a converging direction to grip the wire; the angle of divergence of the facing sloping surfaces of each interchangeable pair of said `wedges being so pre-selected, with respect;v to the roller diameters and theV wire diameter, that said 'rollers will Igrip the wire only after a predetermined `movement of said carriage in a wire feeding ection; whereby a predetermined time delay in the -wire advance during cyclical recit, rocation of said carriage is attained solely by the use of alot-i571 5 a pair of Wedges Whose angle of sloping surface divergence has a predetermined value coordinated With such predetermined time delay.

2. Wire feeding mechanism comprising, in combination, a carriage cyclically reciprocable longitudinally of the Wire and formed for passage of the Wire longitudinally therethrough; a pair of `Wedges interchangeably mounted in said carriage on either side and llaterally spaced from the path of Wire movement therethrough; said Wedges having facing sloping surfaces diverging in the direction lof Wire feed at a preselected slope angle; a pair of rollers rotatable in said carriage in engagement with said sloping surfaces on either side of the path of Wire movement; said rollers, upon movement of said carriage in a wire feeding direction, rolling along said sloping surface in a converging direction to grip the wire; the angle of divergence of the facing sloping surfaces of each interchangeable pair of said Wedges being so preselected, with respect to the roller diameters and the wire diameter, that `said rollers will grip the Wire only after a predetermined movement of said carriage in a lwire feeding direction; whereby a predetermined time delay in the wire advance during cyclical reciprocation of said carriage is attained solely by the use of a pair of wedges whose angle of sloping surface divergence has a predetermined value lcoordinated with such predetermined time delay; and means biasing said rollers in the direction of convergence of said sloping surfaces,

3. Wire feed mechanism as claimed in clai-m 1 including a cage embracing said rollers'.

4. Wire feed mechanism as claimed in claim 3 including a cage embracing said rollers; and means engaging said cage and biasing said rollers in the direction of the conver gence of said sloping surfaces.

5. Wire feed mechanism as claimed in claim 1 in which said carriage is slidably mounted on a support base; a shaft oscillatably mounted in said base; rocker arms secured to said shaft and having free ends operatively connected to said carriage; and crank means operable to oscillate said shaft to reciprocate said carriage.

6. Wire feed mechanism as claimed in claim 5 including a pitman secured to a rotatable crank shaft; and a rod interconnectingr said pitman and said crank means.

7. Wire feed mechanism as claimed in claim 6 in Which said crank shaft, during one--half of each revolution, is ineffective to feed the 'Wire and, during a portion of the other half of each revolution preselectable by the degree of slope of said Wedges moves said carriage in .a Wire feeding direction.

8. Wire feeding mechanism, as claimed in claim 1, in which said carriage comprises a substantially flat body having substantially parallel and flat upper and lower surfaces; said body being lformed with a rectangular aperture therethrough centered 4on the path of wire feed; said wedges being mounted in said rectangular aperture intermediate the upper and lower surfaces of said ibody; a pair of bars associated with each Wedge, the respective bars of each pair being disposed on opposite sides of each wedge and being substantially flush with the respective surface of said body; said bars extending toward each other sulhciently to partially overlap said rollers; and pairs of clamping straps secured to the respective surfaces of said body by removable attachment means and partially overlapping said bars to retain said Wedges and rollers in assembled relation; lwhereby said feeding mechanism may be easily disassembled for inspection and/ or repair by disengaging said attachment means, removing said straps, and removing said bars and Wedges from said rectangular opening along with said rollers.

References Cited in the tile of this patent UNITED STATES PATENTS 833,460 Howe Oct. 16, 1906 1,212,605 Erightman lan. 16, 1917 2,275,269 OLoughlin Mar. 3, 1942 2,696,380 Adams Dec. 7, 1954 2,728,447 Ware Dec. 27, 1955 2,790,541 Friedman Apr. 30, 1957 2,810,573 Nadel Oct. 22, 1957 

1. WIRE FEEDING MECHANISM COMPRISING, IN COMBINATION, A CARRIAGE CYCLICALLY RECIPROCABLE LONGITUDINALLY OF THE WIRE AND FORMED FOR PASSAGE OF THE WIRE LONGITUDINALLY THERETHROUGH; A PAIR OF WEDGES INTERCHANGEABLY MOUNTED IN SAID CARRIAGE ON EITHER SIDE AND LATERALLY SPACED FROM THE PATH OF WIRE MOVEMENT THERETHROUGH; SAID WEDGES HAVING FACING SLOPING SURFACES DIVERGING IN THE DIRECTION OF WIRE FEED AT A PRESELECTED SLOPE ANGLE; AND A PAIR OF ROLLERS ROTATABLE IN SAID CARRIAGE IN ENGAGEMENT WITH SAID SLOPING SURFACES ON EITHER SIDE OF THE PATH OF WIRE MOVEMENT; SAID ROLLERS, UPON MOVEMENT OF SAID CARRIAGE IN A WIRE FEEDING DIRECTION, ROLLING ALONG SAID SLOPING SURFACES IN A CONVERGING DIRECTION TO GRIP THE WIRE; THE ANGLE OF DIVERGENCE OF THE FACING SLOPING SURFACES OF EACH INTERCHANGEABLE PAIR OF SAID WEDGE BEING SO PRE-SELECTED, WITH RESPECT TO THE ROLLER DIAMETERS AND THE WIRE DIAMETER, THAT SAID ROLLERS WILL GRIP THE WIRE ONLY AFTER A PREDETERMINED MOVEMENT OF SAID CARRIAGE IN A WIRE FEEDING DIRECTION; WHEREBY A PREDETERMINED TIME DELAY IN THE WIRE ADVANCE DURING CYCLICAL RECIPROCATION OF SAID CARRIAGE IS ATTAINED SOLELY BY THE USE OF A PAIR OF WEDGES WHOSE ANGLE OF SLOPING SURFACE DIVERGENCE HAS A PREDETERMINED VALUE COORDINATED WITH SUCH PREDETERMINED TIME DELAY. 